In electrical systems electrical power is typically diverted from a utility source to one or more branch circuits via a panelboard. Each of the branch circuits supply power to one or more loads. Typically protective devices, such as circuit breakers, are installed at the panelboard to reduce the risk of electrical overloads and short circuits. An overload occurs when too many loads draw power from a branch circuit, or when a single load draws more than the branch circuit was designed to carry.
In typical installations there may be numerous panelboards and associated branch circuits and an electrician must be aware of the loads on each circuit to properly configure each protective device and load combination. Current transformers (CT's) can be installed and commissioned on each branch circuit at the panelboard. Installation of such CT's, can often be time consuming and cumbersome. Each of the installed CT's may operate to provide a current output signal indicative of the current flow in the respective branch circuit.
The current output signal of each CT may be provided as an input to a digital signal processor included in the panelboard. The digital signal processor may be programmed to provide metering parameters and alarms based on the received current output signals from the CT's. Panelboards that include such installed CT's often require all circuits of the panelboard to be connected to a CT system. In addition, even once the initial installation and setup is done, as users continue to add loads to the branch circuits, there exists the problem of continually overloading the branch circuits. This is because there exists little or no easy way for a typical user to locally monitor the loads on a branch circuit and determine which branch circuits can handle additional loads and which branch circuits are at or near capacity.
Thus, a need exists for a branch circuit monitor system which improves the installation and commissioning of the branch circuits, as well as providing improved local status information to the typical user.